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(in collaboration with the Pain and Neurosensory Mechanisms Branch, NIDCR, NIH)
Reflex Sympathetic Dystrophy (RSD), currently known as Complex Regional Pain Syndrome type I (CRPS-I) has long been recognized clinically. However, RSD is very difficult to diagnosis and track. In this study, the nature of chronic neuropathic pain is assessed using three new techniques: (a) asymmetric thermal pattern between pain and contralateral pain free sites; (b) comparisons of blood flow measured by laser Doppler imaging (LDI) between the two sides; and (c) sympathetic response of blood flow and temperature patterns in the two sides following cold stimulation.
The main purpose of this study is to investigate the applicability of thermography and LDI for tracking the physiological parameters associated with chronic pain before, during and up to five weeks after therapeutic treatment. Asymmetric thermal patterns and sympathetic responses on the two sides after applying cold stimulations are observed. On the other hand, no remarkable difference is observed between the two sides in LDI blood velocity images. The thermal pattern on the most painful side before drug or placebo treatment is typically warmer by at least 1oC spread over a large area. After treatment, thermography shows cooler temperatures on the painful side than the contralateral side.
Typical example of thermal patterns of arms, legs and feet of a normal volunteer.
Typical example of thermal patterns of feet and legs of an RSD patient.
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